The present invention relates to a multi-element ultrasonic transducer for use in an ultrasonic diagnosis system or an ultrasonic treating system.
A multi-element ultrasonic transducer capable of electronic scanning or focusing has such a construction that a plurality of independently operable elements are arrayed. A representative one of the transducers of this kind is composed of an array of elements by dicing a plate-shaped piezoelectric material which has been poled uniformly in a thickness direction, into a plurality of thin elements and by attaching electrodes to the fronts and backs of the thin elements.
In recent years, however, the spatial resolution required for the ultrasonic inspection or measurement advances to the higher and higher level so that the dicing technique required is approaching to the limit. For the high resolution, the ultrasonic frequency has to be made high, or the aperture to be used for transmission or reception of the ultrasonic waves has to be enlarged. In either event, these elements have to be narrowed, which raises a serious problem in dicing operation of the piezoelectric material.
In ULTRASONICS, November 1979, pp. 255-260, on the other hand, there is disclosed a transducer in which electrodes on the surface of a plate-shaped piezoelectric material are disposed separately of one another and in which elements are substantially arrayed without dicing the piezoelectric material. However, the transducer thus fabricated is not desirable as one for the electronic scanning or focusing because a cross talk between the elements is high due to the coupling of the elements.